This invention relates generally to apparatus for use in mounting recessed lighting fixtures in ceilings or the like support surfaces and, more particularly, to plaster frames employed for such purpose.
Conventionally, when recessed lighting fixtures are mounted in ceilings of houses, office buildings, or the like structures, what is commonly known as a "plaster frame" is used to provide support to the lighting fixture housing. A plaster frame is generally a metal member mounted on hanger bars between the joists of the structure supporting the ceiling. The plaster frame generally comprises a main body portion including a rectangular planar member defining an aperture therein surrounded by a depending flange or rim for receipt in a similarly shaped aperture of slightly larger dimension formed in the ceiling surface in which the lighting fixture is to be mounted. An electrical junction box for electrically wiring the fixture is usually also included as a part of the plaster frame.
Oftentimes a plaster frame will also be employed when it is desired to add a recessed fixture in an existing ceiling structure.
Commonly, brackets for receiving the hanger bars on which the plaster frame is mounted between the ceiling joists, are provided at opposite ends of the rectangular planar member of the plaster frame. If the spacing between joists to be used to support a particular plaster frame is such that the plaster frame is improperly dimensioned or if the plaster frame cannot be used because the direction of the run of electrical conduit behind the ceiling is improper, or if there are other difficulties encountered with a particular plaster frame, either another type of plaster frame will be required or a reconstructure of the available plaster frame must be made on the job site so that the plaster frame is usable. To be able to have available several varieties of plaster frames to accommodate various installation requirements, there exists a need for lighting fixture manufacturers to produce, and lighting fixture dealers to maintain in inventory, a number of different types of plaster frames. On the other hand, if a plaster frame is to be reconstructed on the job site, additional time may be required for a fixture installer to modify the plaster frame, causing, in many cases, the cost of the installation to be increased.
In the case wherein a plaster frame is employed to mount a recessed fixture in an existing ceiling, it has sometimes been difficult to mount the plaster frame "behind" the ceiling without creating an opening in the ceiling greater in dimension than the aperture needed for insertion of the lighting fixture, thus requiring repairs to the ceiling subsequent to the mounting of the fixture. To avoid the latter, in many installations of this type, specially designed, more costly lighting fixtures are employed.